Photoactive of Chitosan-ZrO2/TiO2 thin film in catalytic degradation of malachite green dyes by solar light

The large band gap energy of titanium dioxide (TiO2) nanoparticle catalysts hinders them from functioning effectively under solar radiation, encouraging detrimental charge carrier recombination and inadequate adsorption characteristics. Hence, to solve these issues, Chitosan (CS) and Zirconia (ZrO2) were integrated into TiO2 nanoparticles through a sol-gel fabrication method to generate the thin film CS-ZrO2/TiO2 catalyst. CS-ZrO2/TiO2 was found to be in a homogenous spherical form, with particle sizes ranging from 40 to 90 nm, according to micrograph images. Infrared spectroscopy revealed that the Ti–O–Ti, Ti–O-to-NH2, and Ti–O-to-OH groups formed coordinate covalent bonds in the hybrid catalysts. The prominent diffraction peaks identified in XRD spectra confirmed ZrO2. The band gap energies of CS-ZrO2/TiO2 hybrids with diverse Ti/Zr weight ratios were successfully reduced to a value lower than pure TiO2. The photocatalytic activity of CS-ZrO2/TiO2 hybrid with 10% of ZrO2 was proved to be the most efficient photocatalyst with the highest rate constant 9.673 × 10−3 min−1 than pure TiO2 at 2.994 × 10−3 min−1. Photodegradation efficiency of model dyes compounds, malachite green (MG) increased from 11.87% to 30.72% with ZrO2 and CS addition in TiO2 catalyst under solar irradiation. The optimum photodegradation condition lowered the initial MG concentration (5 mg/L) in the acidic medium. From the kinetic study, the improvement of photodegradation efficiency was brought by incorporating ZrO2 into pure TiO2 photocatalyst due to the synergistic energy of both components. [Display omitted] •Homogenous particle distribution of the thin film CS-ZrO2/TiO2 catalyst.•Band gap reduction due to the synergistic energy of hybrid components.•Photodegradation of synthetic dyes increased with addition of ZrO2 under solar light.